<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>对象的扩展</title>
    <script type="text/javascript">
        let arr = [3, 5, 8, 9, 11, 66];

        let result = arr.find(ele=>ele==5);

        console.log(result);

    </script>
</head>
<body>

</body>
</html>